Molar incisor hypomineralization: Analysis of asymmetry of lesions

Clinically, Molar-Incisor Hypomineralization (MIH) lesions are not distributed symmetrically, and their severity varies even within the same arcade.

AIM

To estimate the frequency of asymmetries in hypomineralized lesions on permanent molars and incisors of children with MIH.

METHODS

Three pediatric dentists, calibrated following the diagnostic criteria of Mathu-Muju and Wright (2006) (Kappa 0.87) identified presence and severity of opacities on molars and incisors of patients with MIH. Six pairs of teeth (permanent maxillary and mandibular first molars, central and lateral incisors) were evaluated in each patient. Degree of lesion severity (0-none, 1-mild, 2-moderate, 3-severe) was recorded for each tooth. For each pair containing any affected teeth, asymmetry of presence (one tooth in the pair with lesion and the other intact), asymmetry of severity (both teeth with lesions but with different degrees of severity) or symmetry of severity (both affected teeth with the same degree of severity) were evaluated. The recorded values were entered into a database to calculate percentages, 95% confidence intervals and Chi-Square test for comparisons.

RESULTS

The sample consisted of475 of the 1032 pairs of teeth evaluated in the 172 patients included in the study, mean age 11±2.2 years, and 50% female. Asymmetry was found for 67.5% (63.1 - 71.7) of the pairs of the studied teeth. There was a significant relationship between asymmetries and symmetries (p=0.038). A total 50.1% of the pairs were asymmetrical for presence of opacities. Of these, 62.2% scored severity 1 (mild). Symmetry of severity was found for 32.5% of the lesions. Among the pairs of affected teeth, the most frequently observed degrees of lesion severity were mild and moderate, with the exception of lower molars, in which 49% had severe lesions.

CONCLUSIONS

In this study, MIH lesions were asymmetrical both in presence and severity for all tooth types.

Unilateral supplemental maxillary lateral incisor: report of three rare cases and literature review

Additional teeth to the normal dentition are called supernumerary teeth; they can be found in higher rates in permanent than in deciduous dentition, in both sexes, associated or not with other diseases or syndromes. The aim of this article is to report three rare cases of unilateral supplemental lateral incisors, in Romanian child and adult patients, and to evaluate the treatment options in each case, considering particularities such as age, physiognomy, associated issues and occlusion. The differential diagnosis between a supernumerary lateral incisor in formation and a rudimentary is sometimes difficult to make using only panoramic X-ray, so a cone-beam computed tomography analysis can be indicated. Usually, due to the pathological issues that they can cause, the supplemental maxillary lateral incisors are removed; although, in some cases, it may be necessary to remove the normal tooth, for example in cases of major crowding, in which the normal tooth is more displaced from the line of the arch than the supplemental one, or when there is a lack of periodontal support surrounding the normal tooth. This article highlights that even if, in younger patients, the majority of these teeth is extracted because later in life they can cause difficulties in orthodontic and prosthetic treatment, there are still rare cases which do not necessitate treatment, because they are asymptomatic, rather well aligned and go unnoticed. Also, the article includes a detailed literature review of reported cases of supplemental maxillary lateral incisor.

Short-term and long-term effects of osteoporosis on incisor teeth and femoral bones evaluated by Raman spectroscopy and energy dispersive X-ray analysis in ovariectomized rats

There are few published data on the relationship between loss of bone mass due to osteoporosis and poor tooth quality. This study analyzed the effects of osteoporosis on incisor teeth and femoral bones using optical techniques in rats. Twenty female Wistar rats aged 6 months (n = 20) were randomized into two groups: control group, non-ovariectomized rats (n = 10); ovariectomy group, ovariectomized rats to induce osteoporosis (n = 10). Each group was subdivided randomly into two groups containing five rats each as follows. Control group 1: non-ovariectomized rats euthanized at the age of 9 or 3 months post-ovariectomy (n = 5); Control group 2: non-ovariectomized rats euthanized at the age of 1 year or 6 months post-ovariectomy (n = 5); ovariectomy group 1: ovariectomized rats euthanized at the age of 9 months or 3 months post-ovariectomy (n = 5); ovariectomy group 2: ovariectomized rats euthanized at the age of 1 year or 6 months post-ovariectomy (n = 5). The incisor teeth and femoral bones of Wistar rats were removed to perform Raman spectroscopy using an excitation laser at 785 nm. In addition, an energy-dispersive X-ray spectrometer system was used to evaluate calcium (Ca) and phosphorus (P). The main findings included significant changes (p < 0.05) for phosphate and carbonate band areas for both incisor teeth and femur bones. In addition, there was significant negative correlation between the P concentration and phosphate/carbonate ratio (lower P content-larger ratio, p < 0.05) for incisor teeth and femoral bones. The proline and CH₂ wag band areas were significantly reduced only for the incisor teeth (p < 0.05). Therefore, Raman spectroscopy assessed the compositional, physicochemical and structural changes in hard tissue. The current study also pointed out the possible action mechanisms of these changes, bone fracture risk and dental fragility. It is important to emphasize that poor dental quality may also occur due to osteoporosis.

Bilateral dentoalveolar asymmetries in female patients with adolescent idiopathic scoliosis

PURPOSE

The aim of this cross-sectional research was to quantify left-right dentoalveolar fluctuating (FA) and directional asymmetries (DA) in patients with adolescent idiopathic scoliosis and to assess the relationship between these asymmetries and the side, location, and severity of scoliosis.

MATERIALS AND METHODS

The study group comprised of 60 females aged 12-16 years, with idiopathic scoliosis, and 54 healthy controls. Measurements were made with the use of digital caliper on full-mouth dental casts. The following variables were measured from each subject: a shift of the incisor midline, left and right incisor overjet, deviation of canine and buccal segment relation as well as maxillary and mandibular arch chords. The data were statistically analyzed with significance taken as p < 0.05.

RESULTS

Statistically significant differences in the mean shift of the incisor midline, buccal segment relation on the left and canine deviation on the left between the control group and the study group were detected ( p = 0.0419, p = 0.0.458 and p = 0.0204, respectively). FA of the midline deviation and canine deviation were statistically significantly higher for subjects with IS, compared to healthy controls ( p = 0.0315 and p = 0.0415, respectively). Neither direction of the curve nor apical vertebra's location or apical translation significantly affected the magnitude of dentoalveolar asymmetries.

CONCLUSIONS

Our results confirmed that bilateral asymmetries are a common feature of the young females' occlusion. Individuals with IS show higher tendency to Angle Class II malocclusion, as well as higher FA of incisor midline discrepancy and canine deviation, compared to the controls.

The Prevalence and Severity of Molar Incisor Hypomineralization and Molar Hypomineralization in Dubai, UAE

Purpose: The purpose of this study was to evaluate the prevalence and severity of molar incisor hypomineralization (MIH) among schoolchildren in Dubai, UAE.Methods: A randomized cluster sample of 342 eight to 12-year-old schoolchildren had their permanent first molars and incisors evaluated for prevalence and severity of MIH using the European Academy of Paediatric Dentistry criteria.Results: The prevalence of MIH in Dubai was found to be 27.2 percent and was significantly higher in girls (32.6%) compared to boys (18.1%;P=0.002). The prevalence of molar hypomineralization (MH) was higher than MIH: of the 27.2 percent diagnosed children, 65.6 percent had only MH while 34.4 percent had MIH. MH prevalence in maxillary molars was 20.8 percent, significantly higher than 14.6 percent in mandibular molars (P≤0.005). Almost nine percent of maxillary incisors were affected by MIH compared to 0.9 percent of mandibular incisors (P≤0.001). The presence of demarcated opacities was significantly higher in females than males (P =0.002). Fifty-three percent of the children with MIH had mild defects, 17 percent had moderate defects, and 30 percent had severe defects.Conclusions: Despite the high prevalence of MIH in schoolchildren in Dubai, the severity was mild. The prevalence of MIH and MH was significantly related to sex and location of tooth in the oral cavity.

Association between maxillary lateral incisors' root volume and palatally displaced canines: An instrumental variables approach to the guidance theory

OBJECTIVES:

To evaluate association and causation between maxillary lateral incisors' (MxI2) apical root volume (ARV) and palatally displaced canines (PDC).

MATERIALS AND METHODS:

In a retrospective cross-sectional study, computed tomography scans of 179 patients with unilateral PDC were analyzed. MxI2 root length and volume on the impaction and eruption side were measured. A mixed logit model was used to infer the association between ARV and PDC and an instrumental variables approach to interpret causality.

RESULTS:

MxI2 root length on the impaction side was shorter in 42%, equal in 33% and longer in 25% of the patients. ARV amounted for 13.5% of total root volume on the impaction and 14.9% on the eruption side. Reduced ARV was significantly associated with the impaction side ( P < .001). The causal effect of ARV on PDC in the instrumental variable approach amounted to less than half of the association in a standard noncausal approach.

CONCLUSIONS:

An association between PDC and reduced MxI2 root length and volume was confirmed. However, the lack of causality did not allow the researchers to draw a conclusion as to whether a reduced ARV is causing PDC or resulting from it; this should be considered in etiologic theories.

Tooth wear and gingival recession in 210 orthodontically treated patients: a retrospective cohort study

Aim

To assess the association between tooth wear (TW) and gingival recession (GR).

Materials and Methods

Two hundred and ten orthodontically treated participants (100 males) were evaluated. GR and TW were rated independently by four raters on plaster models at four time points: before treatment (T1), mean age 13.8 years (SD = 3.7); after treatment (T2), mean age 16.7 years (SD = 3.9); 3 years after treatment (T3), mean age 19.7 years (SD = 4.2); and 7 years after treatment (T4), mean age 23.9 years (SD = 4.8). Univariable and mulitvariable random effects logistic regression analyses were performed with scores for GR as dependent variables and with TW, age, gender, dental segments (maxillary and mandibular anterior and posterior segments), time points, and Angle classification as independent variables. Method reliability was assessed with kappa statistics.

Results

Mandibular incisors, mandibular and maxillary first premolars and maxillary first molars were most vulnerable to GR. The prevalence of GR increased during the observation period. At T1 20.5% participants had one or more recession sites, at T4 85.7 % of the participants had at least one GR. There was evidence of association between moderate/severe TW and GR-for a tooth with moderate/severe wear, the odds of recession were 23% higher compared to a tooth with no/mild wear (odds ratio 1.23; 95% CI: 1.08-1.40; P = 0.002). Age, dental segment, and time were also significant recession predictors, whereas gender was not.

Conclusions

There is evidence that moderate/severe TW is associated with the presence of gingival recession. Clinical significance of this can be limited.

U.S. Pediatric Dentists' Perception of Molar Incisor Hypomineralization

Purpose: The purpose of this survey-based study was to target U.S. pediatric dentists in the Midwest region to determine their knowledge, perceptions, and clinical management strategies of molar incisor hypomineralization (MIH). Methods: After obtaining appropriate authorizations, all pediatric dentists identified by the American Academy of Pediatric Dentistry's 2016 to 2017 membership directory in the 12 Midwest states were invited to take part in the study. The questionnaire, adopted from previous studies, incorporated information of the participants' demographics and educational/clinical backgrounds and MIH-focused questions. Descriptive statistics and chi-square tests were used for analysis. An alpha level less than 0.05 was considered statistically significant. Results: A total of 251 out of 975 surveys were completed (26 percent). Nearly all participants were familiar with MIH. The majority reported the MIH prevalence to be less than 10 percent in their clinical practice (62 percent). Most respondents were either very confident (65 percent) or confident (34 percent) when diagnosing teeth with MIH. The most cited clinical challenge in managing MIH teeth was "long-term success of restorations" (79 percent). When analyzed individually, responses differed significantly for different demographics and educational characteristics of the respondents (P<0.05). Conclusion: MIH is generally well acknowledged by U.S. Midwest pediatric dentists, with differences related to their perceptions of the condition's prevalence as well as clinical and restorative management challenges.

Dental enamel defects predict adolescent health indicators: A cohort study among the Tsimane' of Bolivia

OBJECTIVES

Bioarchaeological findings have linked defective enamel formation in preadulthood with adult mortality. We investigated how defective enamel formation in infancy and childhood is associated with risk factors for adult morbidity and mortality in adolescents.

METHODS

This cohort study of 349 Amerindian adolescents (10-17 years of age) related extent of enamel defects on the central maxillary incisors (none, less than 1/3, 1/3 to 2/3, more than 2/3) to adolescent anthropometrics (height, weight) and biomarkers (hemoglobin, glycated hemoglobin, white blood cell count, and blood pressure). Risk differences and 95% confidence intervals were estimated using multiple linear regression. Enamel defects and stunted growth were compared in their ability to predict adolescent health indicators using log-binomial regression and receiver operating characteristics (ROCs).

RESULTS

Greater extent of defective enamel formation on the tooth surface was associated with shorter height (-1.35 cm, 95% CI: -2.17, -0.53), lower weight (-0.98 kg, 95% CI: -1.70, -0.26), lower hemoglobin (-0.36 g/dL, 95% CI: -0.59, -0.13), lower glycated hemoglobin (-0.04 %A1c , 95% CI: -0.08, -0.00008), and higher white blood cell count (0.74 109 /L, 95% CI: 0.35, 1.14) in adolescence. Extent of enamel defects and stunted growth independently performed similarly as risk factors for adverse adolescent outcomes, including anemia, prediabetes/type II diabetes, elevated WBC count, prehypertension/hypertension, and metabolic health.

CONCLUSIONS

Defective enamel formation in infancy and childhood predicted adolescent health outcomes and may be primarily associated with infection. Extent of enamel defects and stunted growth may be equally predictive of adverse adolescent health outcomes.

Finite element investigation of human maxillary incisor under traumatic loading: Static vs dynamic analysis

BACKGROUND AND OBJECTIVE

Traumatic loading is the main form of injury sustained in dental injuries. In spite of the prevalence of dental trauma, little information is available on traumatic dental damage and the evaluation of tooth behavior under traumatic loading. Due to the short period of traumatic loading, at first sight, a dynamic analysis needs to be performed to investigate the dental trauma. However, it was hypothesized that dental traumatic loading could be regarded as quasi-static loading. Thus, the aim of the present study was to examine this hypothesis.

METHODS

Static and dynamic analyses of the human maxillary incisor were carried out under traumatic loading using a 3D finite element method. Also, modal analysis of the tooth model was performed in order to evaluate the assumption of the dental traumatic loading as a quasi-static one.

RESULTS

It was revealed that the static analysis of dental trauma is preferred to the dynamic analysis when investigating dental trauma, mainly due to its lower computational cost. In fact, it was shown that including the inertia of the tooth structure does not influence the results of the dental trauma simulation. Furthermore, according to the modal analysis of the tooth structure, it was found that the mechanical properties and geometry of the periodontal ligament play significant roles in the classification of dental traumatic loading as a quasi-static one, in addition to the time duration of the applied load.

CONCLUSIONS

This paper provides important biomechanical insights into the classification of dental loading as quasi-static, transient or impact loading in future dental studies.

Risk factors associated with open gingival embrasures after orthodontic treatment

OBJECTIVES

To investigate the incidence of and contributing factors to open gingival embrasures between the central incisors after orthodontic treatment.

MATERIALS AND METHODS

One hundred posttreatment patients (29 men and 71 women; mean age, 24.7 years) were divided retrospectively into occurrence and nonoccurrence groups based on intraoral photographs. Based on the severity, the occurrence group was further divided into mild, moderate, and severe groups. Parameters from periapical radiographs, superimposed lateral cephalograms, and study models were compared between the occurrence and the nonoccurrence groups by using independent t-tests and were also analyzed on the basis of severity via analysis of variance. Logistic regression analysis was performed to identify the contributing factors to open gingival embrasures.

RESULTS

The incidence of open gingival embrasures between the central incisors was 22% and 36% in the maxilla and the mandible, respectively. Lingual movement of the incisors, distance from the contact point to the alveolar crest after treatment, antero-posterior overlap of the two central incisors before treatment in the maxilla, and distance from the contact point to the alveolar crest after treatment in the mandible were significantly associated with the occurrence of open gingival embrasures ( P < .05). In the mandible, the amount of intrusion was significantly related to severity ( P < .05).

CONCLUSIONS

The incidence of open gingival embrasures following orthodontic tooth movement is high. Therefore, attention should be paid to the contributing factors to prevent or reduce the occurrence of open gingival embrasures.

Quantitative comparison of incisal tooth wear in patients receiving one-phase or two-phase treatment for skeletal Class III malocclusion with anterior crossbite

OBJECTIVES

The present study aimed to compare the amount of incisal tooth wear in the maxillary central incisors of patients with skeletal Class III malocclusion and anterior crossbite receiving one-phase or two-phase treatment. The hypothesis was that tooth wear would differ according to treatment modalities.

MATERIALS AND METHODS

Maxillary dental casts obtained before (T1) and after (T2) orthodontic treatment were divided into three groups. Group I consisted of casts from 21 patients (7 males, 14 females; mean age 9.8 years) who received two-phase treatment (maxillary protraction followed by fixed appliance therapy). Group II comprised casts from 37 patients who underwent orthodontic camouflage treatment for crossbite, subdivided according to age. Group IIa consisted of casts from 15 adolescents (8 males, 7 females; mean age 13.5 years), and group IIb consisted of casts from 22 adults (13 males, 9 females; mean age 24.5 years). Maxillary dental casts obtained at T1 and T2 were scanned. For each pair of digital images, T2 was superimposed on T1 using the best-fit method. Tooth wear was quantified and compared among groups.

RESULTS

Significantly less tooth wear was observed in group I compared to groups IIa and IIb, but no difference was found between groups IIa and IIb. Spearman correlation analysis revealed no significant correlation between tooth wear and age, treatment duration, or craniofacial morphology.

CONCLUSIONS

Despite the long duration of early treatment, it caused less wear of the maxillary central incisors than did orthodontic camouflage treatment.

Long-Term Effects of Lip Repair on Dentofacial Morphology in Patients with Unilateral Cleft Lip and Palate

Objective

Lateral cephalograms from the growth archive of the Sri Lankan Cleft Lip and Palate Project were analyzed in a cohort design to study the long-term effects of lip repair on dentofacial morphology in patients with unilateral cleft lip and palate.

Methods

A total of 71 patients were recruited, including 23 adult patients with nonsyndromic unilateral cleft lip and palate without surgical repair and 48 adult patients with nonsyndromic unilateral cleft lip and palate who had lip repair, but without management of alveolus or anterior vomer. The design utilized exact matching on ethnicity and statistical control for gender and age.

Results and Conclusions

The data support the hypothesis that lip repair primarily produces a bone-bending effect on the anterior maxillary alveolus (alveolar molding), accompanied by controlled uprighting of maxillary incisors, and secondarily produces a bone-remodeling effect (bone resorption) in the base of the anterior maxillary alveolus. When analyzed by the age at lip repair and the surgeon who performed lip repair, early lip repair produced a greater bone-remodeling effect than did late lip repair, and variation in the surgeon who performed lip repair had an insignificant impact on dentofacial morphology after adjusting for covariates.

Morbidity of Chin Bone Transplants Used for Reconstructing Alveolar Defects in Cleft Patients

Objective

The aim of this study was to evaluate the objective and subjective morbidity of symphyseal chin bone harvesting used for reconstruction of alveolar defects in young cleft patients.

Design

All patients who had undergone chin bone harvesting for alveolar cleft reconstruction in the period from 1992 through 2000 at the Department of Oral and Maxillofacial Surgery of the University Hospital Groningen, Groningen, The Netherlands, were invited to participate in this retrospective study. Patients’ acceptance, perioperative and postoperative morbidity were evaluated. A survey of the medical records was performed. In addition, the patients completed a questionnaire for their appreciation of the procedure. They were also subjected to a clinical and radiographic examination.

Patients

Thirty patients (21 males and 9 females; mean age 11.8 ± 3.6 years) participated in this study.

Results

Neither the medical records nor the experiences of the patients showed significant morbidity. The procedure was appreciated with 6.8 ± 3.5 (scale 0 to 10). Postoperative pain was scored as 1.2 ± 2.5 (scale 0 to 10). Three patients reported transient sensory disturbances at the donor site. Two patients showed a slight sensibility disorder in the symphyseal region. In three patients, an endodontic problem had developed in a lower incisor.

Conclusion

This study showed that chin bone harvesting for reconstructing alveolar cleft in young patients is a well-accepted procedure with low objective and subjective morbidity. Notwithstanding this low morbidity, the patients (and their parents) have to be informed about the risk of objective and subjective disturbances of the sensibility in the donor region and the risk of dental pulp necrosis.

Dentocraniofacial Morphology of 21 Patients with Unilateral Cleft Lip and Palate: A Cephalometric Study

Objective

To assess the skeletal and dental craniofacial proportions of unilateral cleft lip and palate patients who were operated upon using the Malek technique, and compare them with a normal group to highlight the effect of surgical correction on craniofacial development during growth.

Design

Retrospective.

Methods

The cleft palate was closed using the Malek technique in a single operation at 3 months for 11 patients (complete closure of lip and palate) and in a two-stage operation for 10 patients (soft palate at 3 months, lip and hard palate at 6 months). Comparisons were made with a normal control group. Angular and linear measurements of anterior and posterior dimensions of the upper and lower compartments of the face were measured in the 7th and 12th years.

Results and Conclusion

No significant differences were observed between the two groups of palate technique repair, although significant differences were observed between craniofacial dimensions of normal versus cleft lip and palate patients. At a skeletal level, the maxilla and mandible were retrusive relative to the cranial base in the cleft lip and palate group. In fact, there was a backward rotation of the palatal plane with repercussions on the maxillo-mandibular complex position. Furthermore, the maxilla was shorter than in normal patients, whereas the mandible was normally shaped. The upper incisors were retroclined and they locked the lower incisors in linguoversion. There was a posterior skeletal deficit of the respiratory compartment, compensated by more marked posterior maxillary alveolar growth. Facial growth in cleft lip and palate patients followed the same pattern, but was delayed compared with normal patients.

The Crown Size and Sexual Dimorphism of Permanent Teeth in Jordanian Cleft Lip and Palate Patients

Objective:

To provide a detailed description of crown size dimensions in the permanent dentition of Jordanian cleft lip and palate patients and to compare the findings with those of other populations.

Method:

The mesiodistal crown diameters of the permanent teeth of 47 patients with unilateral cleft lip and palate (UCLP), 25 patients with bilateral cleft lip and palate (BCLP), and 74 controls were measured.

Results:

The cleft group (UCLP and BCLP patients) generally demonstrated a smaller tooth size for both the maxillary and mandibular arches than did the control group. A sexual dimorphism pattern with males having larger teeth than females was observed for controls and UCLP patients. More males with BCLP had smaller teeth than did females. In the maxilla, the UCLP cleft-side teeth showed the largest percentage (4%) of sexual dimorphism, whereas the BCLP teeth achieved the highest percentage (3.4%) in the mandible. The UCLP cleft-side maxillary lateral incisors (13.2%) and BCLP mandibular canines (6%) displayed greater sexual dimorphism in crown size than did any other tooth class.

Conclusions:

Tooth size reduction occurred across all permanent tooth types and among early and late-forming teeth in cleft patients compared with the controls. This reduction was more pronounced in the maxillary incisor field. Males with UCLP and control males had larger teeth than did females, whereas a reversal of the normal dimorphism pattern was observed in patients with BCLP.

Relationship between voice function and skeletal effects of rapid maxillary expansion

OBJECTIVE

To evaluate the effects of rapid maxillary expansion (RME) on the vocal quality, maxillary central incisors, midpalatal suture, and nasal cavity in patients with maxillary crossbite.

MATERIALS AND METHODS

Coronal CT scans of 30 subjects (14 boys, 16 girls; mean age, 12.01 ± 0.75) were taken before RME (T0), and at the end of the expansion phase (T1). Voice samples of all patients were recorded with a high-quality condenser microphone (RODE NT2-A) on a desktop computer at T0 and T1. Statistical analyses were performed using a paired-sample t-test. The degree of association between the changes in the voice parameters and nasal width was assessed with Pearson's correlation.

RESULTS

RME treatment produced a significant increase in the transverse dimensions of the midpalatal suture and nasal cavity between T0 and T1 ( P < .05). The maximum F0 and jitter (%) results were shown to decrease statistically significantly from T0 to T1 ( P < .001 and P = .042, respectively). Between T0 and T1, shimmer (%) and shimmer (dB) exhibited statistically significant increases ( P = .037 and P = .019, respectively).

CONCLUSIONS

After RME therapy, voice quality differences were found to be associated with increases in nasal width.

Management of bilateral invasive cervical resorption lesions in maxillary incisors using a novel calcium silicate-based cement: A case report

Invasive cervical resorption is a pathologic process leading to progressive and usually destructive loss of tooth structure. The pathogenic mechanism is not completely understood and the diagnosis may be challenging. The aim of this article is to present an unusual case of bilateral presence of invasive cervical resorption lesions in maxillary central incisors and to discuss the treatment procedures using a novel repair material. The management of the present case was carried out in three phases. The first stage of the treatment aimed at curetting the active tissue from the resorption cavity and restoring the defect with the novel calcium silicate-based cement (Biodentine, Septodont). In the maxillary left central incisor it was not possible to remove the resorptive tissue without exposing the pulp, and therefore root canal treatment was performed. At the second phase, a full-thickness flap was raised in order to expose and repair the defect that was extending subgingivally. At the third phase teeth were restored with composite resin. The patient was kept under review and after a follow-up period of 2 years neither signs of periradicular lesion nor recurrence of resorption were observed. The teeth were asymptomatic, and restorations appeared to be in excellent condition. In conclusion, Biodentine seems to be a promising material for the treatment of invasive cervical resorption lesions.

Comparison of the force levels among labial and lingual self-ligating and conventional brackets in simulated misaligned teeth

Background/objective

The aim of this study was to evaluate force levels exerted by levelling arch wires with labial and lingual conventional and self-ligating brackets.

Materials/methods

The tested orthodontic brackets were of the 0.022-in slot size for labial and 0.018-in for lingual brackets and were as follows: 1. Labial brackets: (i) conventional bracket (GAC-Twin, Dentsply), (ii) passive self-ligating (SL) brackets (Damon-Q®, ORMCO; Ortho classic H4™, Orthoclassic; FLI®SL, Rocky Mountain Orthodontics) and (iii) active SL brackets (GAC In-Ovation®C, DENTSPLY and SPEED™, Strite). 2. Lingual brackets: (i) conventional brackets (Incognito, 3M and Joy™, Adenta); (ii) passive SL bracket (GAC In-Ovation®LM™, Dentsply and (iii) active SL bracket (Evolution SLT, Adenta). Thermalloy-NiTi 0.013-in and 0.014-in arch wires (Rocky Mountain Orthodontics) were used with all brackets. The simulated malocclusion represented a maxillary central incisor displaced 2 mm gingivally (x-axis) and 2 mm labially (z-axis).

Results

Lingual bracket systems showed higher force levels (2.4 ± 0.2 to 3.8 ± 0.2 N) compared to labial bracket systems (from 1.1 ± 0.1 to 2.2 ± 0.4 N). However, the differences between SL and conventional bracket systems were minor and not consistent (labial brackets: 1.2 ± 0.1 N for the GAC Twin and 1.1 ± 0.1 to 1.6 ± 0.1 N for the SL brackets with 0.013-in thermalloy; lingual brackets: 2.5 ± 0.2 to 3.5 ± 0.1 N for the conventional and 2.7 ± 0.3 to 3.4 ± 0.1 N for the SL brackets with 0.013-in Thermalloy).

Limitations

This is an in vitro study with different slot sizes in the labial and lingual bracket systems, results should be interpreted with caution.

Conclusions/implications

Lingual bracket systems showed higher forces compared to labial bracket systems that might be of clinical concern. We recommend highly flexible nickel titanium arch wires lower than 0.013-in for the initial levelling and alignment especially with lingual appliances.

Comparison of Cephalometric Hard and Soft Tissues of Adolescents with Angle Class II Division 1 Malocclusion between Northern Chinese Population and Northern Indian Population

OBJECTIVE

To determine if there was a difference in hard and soft tissue between northern Chinese and northern Indian adolescents with Angle Class II division 1 malocclusion.

METHOD

A total of 40 Angle Class II division 1 patients, including 20 boys and 20 girls aged 10 to 13 years with no prior treatment, were selected from northern China and northern India, respectively. Overall, 80 cephalometric data were analysed based on two-sample t-test with SPSS software.

RESULTS

The Chinese subjects had larger anterior facial height and mandibular plane angle. Analysis of dentoalveolar complex showed that the Chinese subjects had more proclined incisors, protruding upper lips and more upper posterior tooth height than that of the Indian subjects. The length of the maxilla and mandible was larger in the Indian subjects than that of the Chinese subjects, but the length of mandible was not significantly different between the two groups.

CONCLUSION

Compared with the Indian subjects, the Chinese subjects with Class II division 1 malocclusion had less prognathic maxillas, more protruding lips, steeper mandibular plane angles and more proclined maxillary incisors. Within the same gender, the Indian boys had more protruded faces and Indian girls had more protruded maxillas, steeper mandibular plane angles and fuller lips.

Conservative, Functional, and Esthetic Rehabilitation of Severe Palatal Erosion (Class IV) Using Modified Dahl Approach

This article demonstrates the clinical application of biomechanical and occlusal principles to conservatively provide optimal clinical outcomes in restoring an eroded anterior dentition. The authors manage a challenging case involving limited palatal clearance (ie, deep bite) coupled with palatal erosion and wear by combining the centric relation (CR) and Dahl principles to create anterior interocclusal space to reduce the need for more invasive palatal reduction. The combined use of adhesive restorations-resin composites on the palatal surface and indirect porcelain veneers on the facial/incisal surfaces-through enamel and dentin bonding helped optimize esthetic and functional/biomechanical aspects. This ultraconservative approach enabled the desired esthetic and biomechanical outcomes to be achieved through the treatment of localized anterior tooth erosion and wear. In short, when treating eroded maxillary anterior teeth with deep bite, adequate restorative space should first be created by conjoining CR and Dahl principles before using adhesive dentistry to restore with bonded composites and porcelain veneers.

Hypodontia: An Update on Its Etiology, Classification, and Clinical Management

Hypodontia, or tooth agenesis, is the most prevalent craniofacial malformation in humans. It may occur as part of a recognised genetic syndrome or as a nonsyndromic isolated trait. Excluding third molars, the reported prevalence of hypodontia ranges from 1.6 to 6.9%, depending on the population studied. Most affected individuals lack only one or two teeth, with permanent second premolars and upper lateral incisors the most likely to be missing. Both environmental and genetic factors are involved in the aetiology of hypodontia, with the latter playing a more significant role. Hypodontia individuals often present a significant clinical challenge for orthodontists because, in a number of cases, the treatment time is prolonged and the treatment outcome may be compromised. Hence, the identification of genetic and environmental factors may be particularly useful in the early prediction of this condition and the development of prevention strategies and novel treatments in the future.

[Diagnossis and treatment of complicated anterior teeth esthetic defects by combination of whole-process digital esthetic rehabilitation with periodontic surgery]

OBJECTIVE

To explore a new method of whole-process digital esthetic prosthodontic rehabilitation combined with periodontic surgery for complicated anterior teeth esthetic defects accompanied by soft tissue morphology, to provide an alternative choice for solving this problem under the guidance of three-dimensional (3D) printing digital dental model and surgical guide, thus completing periodontic surgery and digital esthetic rehabilitation of anterior teeth.

METHODS

In this study, 12 patients with complicated esthetic problems accompanied by soft tissue morphology in their anterior teeth were included. The dentition and facial images were obtained by intra-oral scanning and three-dimensional (3D) facial scanning and then calibrated. Two esthetic designs and prosthodontic outcome predictions were created by computer aided design /computer aided manufacturing (CAD/CAM) software combined with digital photography, including consideration of white esthetics and comprehensive consideration of pink-white esthetics. The predictive design of prostheses and the facial appearances of the two designs were evaluated by the patients. If the patients chose the design of comprehensive consideration of pink-white esthetics, they would choose whether they would receive periodontic surgery before esthetic rehabilitation. The dentition design cast of those who chose periodontic surgery would be 3D printed for the guide of periodontic surgery accordingly.

RESULTS

In light of the two digital designs based on intra-oral scanning, facing scanning and digital photography, the satisfaction rate of the patients was significantly higher for the comprehensive consideration of pink-white esthetic design (P<0.05) and more patients tended to choose priodontic surgery before esthetic rehabilitation. The 3D printed digital dental model and surgical guide provided significant instructions for periodontic surgery, and achieved success transfer from digital design to clinical application. The prostheses were fabricated by CAD/CAM, thus realizing the whole-process digital esthetic rehabilitation.

CONCLUSION

The new method for esthetic rehabilitation of complicated anterior teeth esthetic defects accompanied by soft tissue morphology, including patient-involved digital esthetic analysis, design, esthetic outcome prediction, 3D printing surgical guide for periodontic surgery and digital fabrication is a practical technology. This method is useful for improvement of clinical communication efficiency between doctor-patient, doctor-technician and doctors from different departments, and is conducive to multidisciplinary treatment of this complicated anterior teeth esthetic problem.

[Clinical evaluation of periodontal-orthodontic treatment in patients with aggressive periodontitis and malocclusion]

OBJECTIVE

To evaluate the clinical effect and safety of periodontal-orthodontic treatment in patients with aggressive periodontitis (AgP) and malocclusion.

METHODS

A retrospective analysis was conducted in 25 AgP patients, who had received periodontal-orthodontic treatment in Peking University School and Hospital of Stomatology. Clinical indexes, including probing depth (PD), bleeding index (BI) and percentage of sites with bleeding on probing (BOP%) were evaluated at three time points: Baseline (T0); active periodontal treatment finished and before orthodontic treatment (T1); and after orthodontic treatment (T2). Also changes of ratio of the residual alveolar bone height (RBH) and the occurrence of root resorption were evaluated by periapical radiographs.

RESULTS

(1) Compared with T0, all the clinical parameters including PD, BI, BOP% and percentage of sites with PD>3 mm were significantly improved (P<0.001). (2) Significant difference was observed in the average RBH between T0 (68.37%±15.60% and T2 (70.27%±14.23%). RBH in upper incisors [(58.79%±16.71% at T0, 65.54% (55.74%, 78.13%) at T2], upper canines [77.62% (66.06%, 87.17%) at T0, 79.57% (69.75%, 86.52%) at T2] and upper molars [74.30% (61.69%, 84.45%) at T0, 76.76% (68.12%, 85.09%) at T2] showed significant increase (P<0.05). (3) After orthodontic treatment, varying degrees of root resorption occurred in (23.94%±13.45%) of teeth per capita, among which the lower and upper incisors showed the highest incidence (68.48% and 65.31% in homogeneous teeth, respectively).

CONCLUSION

After active periodontal treatment, orthodontic treatment in AgP patients had not aggravated inflammation and alveolar bone resorption; root resorption occurred in two-thirds of incisors approximately.